基于拓扑绝缘体表面/边缘态纳米结构量子输运及调控研究

拓扑绝缘体(TI)是一种由自旋轨道耦合导致的量子物态，体态是绝缘体而表面/边缘态则是受时间反演对称性保护自旋分辩的金属，展现许多新奇量子效应和电磁特性，在未来高速低耗(自旋)电子器件和量子计算等领域具有广阔应用前景。目前3DTI的研究主要是针对2D表面态，功能结构器件的设计需要认识表面态在打破2D空间平移对称性基础上的准一维(Q1D)体系的基本性质。本项目针对金属侧电极与铁磁条在表面形成的量子波导、单根纳米条带等基于Bi2Se3系列3DTI表面的纳米结构，研究条带上下表面间及其与侧表面的耦合、受限波导模式结构、子能级分布与带隙的变化、无序与相互作用、铁磁近邻效应以及透射率和磁阻等电子结构与自旋输运性质及外场调控中的基础物理问题。项目的特色和创新是将发展和建立基于TI表面态Q1D体系的理论和处理方法。这类研究对进一步认清TI表面态的物理本质、探索基于表面态的光电器件设计具有重要意义。

Topological insulators (TIs) are new states of quantum matter orignating from spin-orbit coupling, which are characterized by a full insulating gap in the bulk and gapless surface/edge states protected by time-reversal symmetry. TIs exhibit many new quantum effects and electromagnetic features, and may be extensively used in spintronic devices with high speed and low consumption as well as quantum computing. The previous researches have been mainly for 2D surface states, but the design of low-dimension functional devices requires the knowledge of the nature of quasi-one-dimensional (Q1D) systems under the breaking of 2D translational invariance. This project will focus on experimentally realized waveguides and their nanostructures on the surface of B12Se3 crystal by gate-electrodes and nanoribbons, and investigate their electronic structure and transport properties, such as subband distribution, formation of gap, spin polarization, hybridization of surfaces, disorders and interactions, ferromagnetic proximity, transmission and magnetoresistance and etc. The main characteristic and innovation in the proposal is to complete and develop the theory and method for Q1D systems based on 3DTI, and this has the important significant for the further understanding of the nature of TI surface states and designing of electronic device.